The invention relates generally to flexible command and control of an autonomous surface vehicle. In particular, the invention provides a stratified structure of instructions to achieve a mission objective operating within constraint protocols.
Conventional operational methods employ remote control signal devices provided by a human that views sensor information from the unmanned vehicle or from other sources to send steering commands to the vehicle. Some limited autonomy is available for situations without obstacles, traffic, or enemy in which waypoints are issued to the surface vehicle follow with a simple autopilot on board. The vehicle uses Global Positioning System or a similar system to hold the boat on bearing to the next waypoint. Commercial boat autopilots are available for this purpose for commercial and recreational boating applications to reduce human workload. For these systems, human monitoring remains necessary in the event of traffic or obstacles. For such situations or when the weather obscures visibility or interferes with stability, direct human control of the vehicle steering is required to ensure operational safety and achievement of the vehicle's mission.
An example of where direct human intervention is required is the case of steering relative to an oncoming wave to prevent rollover. Operations such as docking or rendezvous with a command platform all require direct human control of the ship steering. In a situation where the USV supports combat operations, there can be traffic present (including both friendly and hostile) which require human intervention to direct the activities of the vehicle by remote control. In addition, complex missions such as intercepting a potentially hostile incoming boat would require direct human control via a remote link.
Some autonomy is available in missile and aircraft autopilot and missile guidance systems. Aircraft and missile autopilots deal with narrowly defined missions such as stabilization of the aircraft or execution of a commanded turn to a new heading. These automated functions are fairly limited in nature and are designed to work in a rather scripted process.
The greatest amount of autonomy in aircraft systems occurs in the microburst recovery systems for commercial aircraft. Because the limited time required to respond stresses the human reaction time, consensus is developing of the utility to provide limited autonomy to the system to fly the vehicle out of the microburst. This represents a very scripted and optimized flight procedure. Trajectory guidance for an autonomous land attack cruise missile follows a scripted mission without significant flexibility. This limits autonomous operation to a fire-and-forget weapon such as the Tomahawk cruise missile, rather than an unscripted reconnaissance platform such as the Global Hawk aircraft that requires real time flexibility.
Current methods for controlling an unmanned surface vehicle require increased manning requirements for the command platform operating that surface vehicle. Additionally, the current approach to remote control operation of unmanned vessels exhibits decreased functionality during certain periods because the human operators degrade by fatigue or lack of trained personnel. There are also limitations on the mission because of the limited human capabilities. Advanced automatic systems are anticipated be able to pilot the ship in inclement weather conditions better than human operated systems. This arises from the ability to design the system to use sensor input rather than organic feedback to a human operator such as Doppler measurement of water speed and from the faster response time of automated systems.